screen.seqs get stuck after some time?

I’m using SOP for MiSeq and I have reached the screen.seqs. But every time I run the following command after some time it gets stucked on a random “Processing sequence: XXXXX” and I notised with top the decreased CPU from 16 or 8 to 1 CPU. Than I even get out quite difficult with Ctrl-C

mothur > screen.seqs(fasta=stability.trim.contigs.unique.align, count=stability.trim.contigs.count_tab
le, summary=stability.trim.contigs.unique.summary, start=2, end=17012, maxhomop=8, processors=16)

I have tryed with 8 processors, than 4, but is the same.

My CPU are 48 , 128RAM, 24TB array.

Here is the pastebin of a log -